A good battery should meet four basic requirements. It must have a high energy density, if a light and compact design is to supply as much energy as possible. It should deliver high levels of power and be rechargeable within a short time. Finally, it should be stable enough to withstand thousands of charge/discharge cycles without detriment to efficiency.

Network of nanoscale lithium titanate crystals.

The combination of fast rechargeability with high stability is a tall order, but LMU researchers Professor Thomas Bein and Dr. Dina Fattakhova-Rohlfing, who are affiliated with the Excellence Cluster “Nanosystems Initiative Munich” (NIM), have developed molecular architectures that set new standards in this area.In the current issue of Angewandte Chemie (International Edition), they and their coworkers describe a nanostructure that significantly surpasses the performance levels attainable with conventional storage systems.

Rapid recharging

The new storage medium is fabricated by heating lithium titanate crystals at 400°C in the presence of polymers, which results in the formation of a porous framework of interconnected nanocrystals. With this new structure, the researchers were able to break all previous records. The lithium titanate network can be completely recharged in a matter of seconds and discharged on demand. For comparison, charging of a related nanostructure was previously reported to take more than a minute.

The Munich researchers also showed that the new matrix tolerated repeated charge/discharge cycles with no deterioration. Even after 1000 cycles, recharging times were unchanged. “These extremely fast storage electrodes have great potential for the development of more efficient batteries,” asserts Thomas Bein. “And they may help to close the gap between supercapacitors and classical batteries.”